Selector switch



Patented Dec. 22, 1942 UNlTED STATES PATENT OFFICE.

1 Claim.

My invention relates to a switch for selectively closing electricalcircuits, such as test circuits for radio tubes.

It is among the objects of my invention to provide a selector switchoperated by a key.

Another object is to provide a key operated switch by which circuits areselectively established in accordance with characteristics of aparticular key used to operate it.

A further object is to provide a key operated switch for radio testcircuits, whereby circuits for difierent types of tubes may beestablished by merely using different keys for operating the switch.

A still further object is to provide an improved arrangement of contactarms and terminals on the switch.

The invention possesses other objects and features of advantage, some ofwhich, with the foregoing, will be set forth in the followingdescription of my invention. It is to be understood that I do not limitmyself to this disclosure of species of my invention, as I may ado-ptvariant embodiments thereof within the scope of the claim.

Referring to the drawing:

Figure l is a vertical sectional View of the switch with portions of theforward side plate shown in elevation to illustrate the key slot.

Figure 2 is an end elevational view of the switch; and

Figure 3 is a fragmentary horizontal sectional view showing the key inclosed switch position.

Figure 4 is a detail elevational view showing a series of terminals anda pair of associated contact arms; and

Figure 5 is a plan view of the same.

Figure 6 is a detail sectional view showing the brush of a contact arm.

In terms of broad inclusion, the selector switch of my inventioncomprises a contact arm, and key operated means for moving the arm to apredetermined position. A plurality of such contact arms ar preferablyprovided for selective engagement with a plurality of terminals toestablish difierent circuits connected therewith. The operating meanspreferably comprises a key having a plurality of spaces engageable withthe arms for moving the latter to predetermined positions upon turningth key. With this switch different groups of circuits, such as radiotest circuits may be selectively closed depending upon the shapecharacteristics of different keys for operating the switch. Thus, onekey may be designed for closing circuits to test one type of radio tube,and another key may be designed for ranged in rows at the top of theframe.

closing circuits to test another type of tube. It is understood that thesuggested use of my switch for radio test circuits is merely forpurposes of illustration, and that the device may be used wherever aselector switch is desired.

In greater detail, and referring to the draving, my switch comprises aframe having side plates 2 and an inclined bottom plate 3. A pluralityof contact arms 4 are pivotally mounted on the frame on a rod 6extending transversely between the central portions of plates 2, thusmounting the arms for pivotal movement about a common axis. Collars Iabout rod 6 hold the arms properly spaced, and suitable springs 8normally retain the arm in retracted position with the upper endsaligned. The lower ends of the arms are preferably bent to equally spacethe latter for registration with guide slot 9 in bottom plate 3, throughwhich pointed ends ll of the arms project. Abutment of arm ends H withthe ends of the slot serves as limit stops for the arms in retractedposition.

A plurality of series of terminals I2 are ar- These terminals arefastened to arcuate insulating strips l3 held by cross rods 14 betweenside plates 2. In the structure shown, three rows of the terminals areillustrated with nine terminals in each row, but it is understood thatboth the number of rows and number of terminals therein may be varied,as may also be the number of contact arms 4, there being twice as manyarms as rows of terminals. Each terminal is secured to its mountingstrip l3 by a rivet I6 having a head to provide a contact on the side ofthe strip opposite the terminal as shown in Figure 6.

Along each side of strip I3 is mounted another insulating strip llspaced by collars I8 on rods 14. On each strip I1, facing the row ofterminals, is a contact bar [9 secured by rivet 2t. An end terminal 2|fastened by one of these rivets provides a circuit connection for thebar. A terminal unit as shown in Figur 5 is thus made up of a row orseries of the terminals I2, and a pair of contact bars 19. There beingthree rows of terminals in th structure illustrated, there are three ofthese terminal units.

Means are provided on contact arms 4 for bridging a bar H! with one ofthe associated terminals l2. For this purpose a brush 22 is mounted onthe upper end of each arm, comprising a connected pair of flexiblestrips riveted to an insulating piece 23 secured to the arm. A pair ofarms 4 is associated with a terminal unit with a brush 22 interposedbetween each contact bar l9 and the row of terminals, one of the brushesengaging directly with a terminal and the other brush making contactwith a terminal through its rivet l6. Thus, circuit leads connected tocontact bars I9 through end terminals 2| may be selectively connectedwith other circuit leads secured to terminals 12, the particularcircuits closed depending upon the position of arms 4.

Key operated means are provided for moving arms 4 to predeterminedpositions. As best shown in Figures 1, 2 and 3, a key having a handle 26and a head 21 is provided for insertion through frame block 28 to anoperating position adjacent arm 4. A rounded core portion 29 of the keyseats in a hollow, slotted rotor 3i journaled in the frame plates togive support for the key when the latter is turned. Head 21 of the keyis preferably a flat plate having offset spaces 32 cut as steps alongthe edge of the plate. These spaces register with arms 4, and, when thekey is turned to the horizontal position shown in Figure 3, the arms aremoved to varying extended positions depending upon the shapecharacteristics of the key.

In the extended position of arms 4, the brushes make contact withselected terminals to close predetermined circuits. For closing othercircuits a different key may b used. For example, in connection withradio test circuits a different key would be provided for differenttypes of tube for establishing the necessary connection for a particulartube. This selector switch is thus a great convenience for quicklyclosing predetermined circuits for the many different types of tubes nowrequired to be tested.

I prefer to provide a key having a head plate extending in oppositedirection, with differently arranged offset spaces 33 cut in theopposite edge. Thus, the arms are moved to predetermined position whenthe key is turned in one direction, and are moved to other positionswhen the key is turned in the opposite direction. Spaces 33 of the keymay be designed for establishing connection to test for shorts. Keyswith three operating plates could be provided.

While I have described my device as a switch, it is understood that thekey operated mechanism may be designed as a rheostat, in which case arms4 would function as contact arms for resistance elements.

I claim:

A selector switch comprising a plurality of series of terminals, aplurality of contact arms each selectively engageable with the terminalsof a series, and a key having oppositely disposed faces for engaging thearms when the key is turned in either direction, one of said faces beingshaped to move the arms into engagement with a selected combination ofterminals when the key is turned in one direction and the other facebeing shaped to move the arms into engagement with another combinationof terminals when the key is turned in the opposite direction.

CHARLES L. HOWARD.

